| 摘要 |
PURPOSE:To easily secure waterproof performance by using a piezoelectric element for both an acoustic output deice and an input device. CONSTITUTION:Input signals A and B are inputted to an AND gate 1. Here, the signal A is an alarm tone driving signal and the signal B is an alarm driving control signal. When this signal B is at a logical level '1', the gate 1 outputs an alarm driving signal to drive the piezoelectric element 4 through piezoelectric elements 2 and 3, thereby generating a tone. Then an input connecting circuit 5 enters a half state because the signal is at the level '1', and an input control circuit 6 and the element 4 are disconnected. Then when the signal B varies to a logic level '0', a driver 2 outputs the logical level '1', which becomes a floating output; and the circuit 5 becomes ready to operate and a signal is inputted to the circuit 6 with the generated voltage of the element 4. Namely, the rear lid of the timepiece is pressed in this state and then the element 4 stuck on the rear lid generates a voltage, which is inputted as an input signal to the circuit 6. |
